Elastic and rotationally inelastic scattering of fluorine atoms by deuterium molecules at 112 meV collision energy

The F + D-2 elastic scattering as well as the D-2(j(i) = 0 -->j(f) = 2), D-2(j(i) = 1 --> j(f) = 3) and, for the first time, D-2(j(i) = 0 j(f) = 4) inelastic rotational transitions have been measured in a crossed molecular beam experiment ata center-of-mass collision energy of 112 +/- 2 meV. Differential cross-sections for the measured rotational transitions have been calculated on three different potential energy surfaces (Takayanagi-Sato, DMBE-6SEC of Truhlar and coworkers, and Stark-Werner) using different quasiclassical and semiclassical techniques. Although an overall qualitative agreement is found between the experimental and computed differential cross-sections, significant discrepancies are also apparent. In particular, the dynamical calculations lead to a systematic underestimation of the scattering yield into the non-reactive scattering channels, which can be attributed to shortcomings in the topography of all the three surfaces probed. Replacing the free deuterium molecule with a rigid or a vibrating rotor (both of these models exclude reaction) in the dynamical treatment considerably reduces the disagreement between the experimental and the calculated differential cross-sections for the different inelastic transitions. (C) 1998 Elsevier Science B.V.